Gearbox control device

ABSTRACT

A transmission control device ( 6 ) for an automatic or automated transmission ( 2 ). A shifting strategy of the transmission control device ( 6 ) controls and/or regulates the operation of the transmission ( 2 ) based on driving condition data such as vehicle mass, driving resistance, vehicle inclination, vehicle velocity, vehicle acceleration, engine rotational speed and/or engine torque, and based on data about the driver&#39;s wishes. The transmission control device ( 6 ) continuously calculates the driving condition data of the vehicle mass, driving resistance and/or vehicle inclination based on topographic data of a current position of the motor vehicle, and/or the shifting strategy determines a gear change from an actual gear into a target gear based on topographic data of a defined distance ahead of a motor vehicle. The defined distance ahead of the motor vehicle depends on the currently velocity of the vehicle.

This application is a divisional of U.S. patent application Ser. No.13/263,858 filed Oct. 11, 2011, which is a National Stage completion ofPCT/EP2010/052809 filed Mar. 5, 2010, which claims priority from Germanpatent application serial no. 10 2009 002 387.9 filed Apr. 15, 2009.

FIELD OF THE INVENTION

The invention relates to a gearbox control device.

BACKGROUND OF THE INVENTION

The main components of a drive train of a motor vehicle are a driveassembly and a transmission. The transmission converts rotational speedsand torques of the drive assembly, and provides the tractive power ofthe drive assembly at an output drive of the drive train. The operationof the drive assembly is controlled and/or regulated by an enginecontrol device. The operation of the transmission is controlled and/orregulated by a transmission control device. In a transmission controldevice, which controls and/or regulates the operation of a motor vehicletransmission preferably built as an automatic, or automated,transmission, a shifting strategy is implemented where the shiftingstrategy of the transmission control device controls or regulates theoperation of the transmission based on the driving condition data andthe data of the driver's wish. The shifting strategy determines, inparticular, a change of gears from an actual gear to a targeted gearbased on the driving condition data and the data of the driver'srequest.

A transmission control device, disclosed in DE 10 2006 001 818 A1,evaluates the topography of the travel route ahead of the motor vehiclein order to determine a gear change with the support of a computer, forexample.

The patent, DE 10 2007 025 502 A1, discloses a transmission controldevice that controls the transmission depending on information about theenvironment of the motor vehicle, in particular based on informationabout route inclines and progressions. In the process, the transmissioncontrol device also evaluates information about the environment of themotor vehicle, such as that sent from traffic guidance devices.

Although it is already fundamentally known from the prior art that atransmission control device controls and/or regulates the operation ofthe transmission based on data concerning the environment of the motorvehicle, in particular on the basis of topographic data, there is acontinued need to further improve the operation of a transmission on thebasis of such data, in particular to ensure the lowest possible fuelconsumption while simultaneously providing the greatest possible agilityof the motor vehicle. Therefore, a transmission control device isneeded, which further develops transmission control devices known fromthe prior art, so that the greatest possible vehicle agility isguaranteed with the lowest possible fuel consumption.

SUMMARY OF THE INVENTION

Proceeding therefrom, the problem addressed by the present invention isto create a novel transmission control device.

This objective is solved, according to the first aspect of the inventionin which the transmission control device continuously calculates thecurrent vehicle driving condition data, vehicle mass and/or drivingresistance and/or vehicle inclination based on the topographic data of acurrent position of the motor vehicle.

According to the second aspect of the invention, the shifting strategyof the transmission control device determines a gear change from acurrent actual gear into a targeted gear based on topographic of adefined distance ahead of the current position of the motor vehicle,wherein the defined distance ahead of the current position of the motorvehicle is determined depending on the vehicle velocity.

Both aspects of the present invention provide transmission controldevices that guarantee the greatest possible agility of a motor vehiclewith the lowest possible fuel consumption. For this purpose, accordingto the first aspect of the present invention, the current drivingcondition data, vehicle mass, and/or driving resistance and/or vehicleinclination, which are used as input data for a shifting strategy, arecontinuously calculated based on topographic data of a current positionof the motor vehicle. According to a second aspect of the invention,which can be used in combination with the first aspect, the shiftingstrategy of the transmission control device determines a gear changebased on topographic data of a defined distance ahead of the currentposition of the motor vehicle, wherein the defined distance ahead of themotor vehicle depends on the vehicle velocity of the motor vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred further developments of the invention will become apparentfrom the description that follows. An embodiment of the invention isdescribed in more detail, without being restricted thereto, based on thesole FIGURE which shows:

a block diagram for illustrating the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The FIGURE shows a highly schematic representation of a drive train of amotor vehicle, wherein the drive train of the FIGURE comprises a driveassembly 1 and a transmission 2, wherein the transmission 2 is arrangedbetween the drive assembly 1 and an output drive 3 of the drive train.The transmission 2 is preferably built as an automatic, or automated,transmission and converts rotational speeds and torques of the driveassembly 1 and thus provides the tractive power of the drive assembly 1at the output drive 3. According to the FIGURE, a start-up clutch 4 isconnected between the drive assembly 1 and the transmission 2.

An engine control device 5 is assigned to the drive assembly 1, and atransmission control device 6 is assigned to the transmission 2. Theoperation of the drive assembly 1 is controlled and/or regulated usingthe engine control device 5, for which purpose the drive assemblyexchanges data 7 with the engine control device 5. The operation of thetransmission 2 is controlled and/or regulated by transmission controldevice 6, for which purpose the transmission control device 6 exchangesdata 8 with the transmission 2. According to the FIGURE, the enginecontrol device 5 also exchanges data 9 with the transmission controldevice 6.

According to the FIGURE, the transmission control device 6 is suppliedwith not only the data 8 from the transmission 2, and data 9 from theengine control device 5, moreover the transmission control device 6 isprovided with further data 10 from sensors 14 for example, on the basisof which the transmission control device 6 controls and/or regulates theoperation of the transmission 2.

In addition, data 12 about the environment or topography of the motorvehicle is provided from a navigation device 11 to the transmissioncontrol device 6, specifically both data about the topography orenvironment of the current position of the motor vehicle as well as dataabout the topography or environment of motor vehicle of a defineddistance ahead of the current position of the same motor vehicle.

The transmission control device 6 controls and/or regulates theoperation of the transmission 2 on the basis of driving condition dataand data about the driver's wishes. In particular, a shifting strategy,which determines a gear change from the current actual gear into atargeted gear on the basis of driving condition data and data about thedriver's wishes, is implemented in the transmission control device 6.

For this purpose, the transmission control device 6 uses vehicle massand/or driving resistance and/or vehicle inclination and/or vehiclevelocity and/or vehicle acceleration and/or engine rotational speedand/or engine torque as driving condition data. Data about the actuationof an accelerator pedal and data about the actuation of the brake pedalof the motor vehicle in particular are supplied to the transmissioncontrol device 6 as data about the driver's wishes.

Engine rotational speed and/or engine torque are preferably providedfrom the engine control device 5 as data 9 to the transmission controldevice 6. The driving condition data, vehicle inclination and vehiclevelocity as well as vehicle acceleration, are preferably supplied to thetransmission control device 6 as data 10 from external sensors, wherethe vehicle acceleration can alternatively also be calculated within thetransmission control device 6.

According to a first aspect of the invention, the transmission controldevice 6 continuously calculates the driving condition data, vehiclemass and/or driving resistance and/or vehicle inclination on the basisof topographic data 12 of a current position of the motor vehicle, so asto assure in the shifting strategy a more precise gear change, on thebasis of such continuously determined driving condition data, providinga greatest possible agility of the motor vehicle with the lowestpossible fuel consumption.

According to a preferred advantageous further development of theinvention, upon switching on the ignition of the motor vehicle or duringa standstill of the motor vehicle with the ignition switched on, thetransmission control device 6 calibrates an inclination sensor, which isinternal or external to the transmission, based on topographic data 12of the current position of the motor vehicle.

For this purpose, the transmission control device 6 calculates thecurrent vehicle inclination from the topographic data 12 of the currentposition of the motor vehicle, and with this corrects the correspondingmeasured value of the inclination sensor.

Preferably this calibration occurs every time the motor vehicle ignitionis switched on, wherein if upon switching on the ignition of the motorvehicle no topographic data is available for the current position of themotor vehicle, the calibration is deferred until the next vehiclestandstill, for example at the next red traffic light.

According to an advantageous further development of the invention,during travel of the motor vehicle, the transmission control device 6continuously calculates the current driving resistance of the motorvehicle from the topographic data of the current position of the motorvehicle, aerodynamic resistance fraction, rolling resistance and avehicle mass. In this context it can be provided that the transmissioncontrol device 6 calculates the current rolling resistance and also therolling resistance coefficient from the topographic data of the currentposition of the motor vehicle, a current tractive force of the driveassembly 1, a current vehicle acceleration and a current aerodynamicresistance fraction. For this purpose, the current tractive force of thedrive assembly 1 can be derived from the current engine torque. Thecurrent vehicle acceleration can be determined either throughmeasurement or calculated from the current vehicle velocity. The rollingresistance and the rolling resistance coefficient are stored in a memoryfor later use.

Then, when a rolling resistance is established, the current drivingresistance can also be calculated independently of the engine torque. Inthe case where the current driving resistance is calculated withoutconsidering the engine torque, the engine torque can be corrected fromthe engine rotational speed for specific driving situations, in whichthe engine torque is required, depending on characteristic values. Thecorrected values are stored in a memory.

According to another advantageous further development of the invention,during travel of the motor vehicle, the transmission control device 6continuously calculates the current vehicle mass from the topographicdata 12 of the current position, aerodynamic resistance, rollingresistance and from a current vehicle acceleration and/or a currenttractive force. Again, for this purpose, the vehicle acceleration can bedetermined through measurement or calculation from the current vehiclevelocity. The rolling resistance of a motor vehicle can either be givenas a fixed variable or variably calculated from the current tractiveforce. Preferably the calculation of the current vehicle mass occursduring every startup of the motor vehicle from a standstill of thevehicle.

In this context it can be provided that the transmission control device6 only recalculates the vehicle mass under specific driving conditionsthat depend on topographic data 12 of the current position of a motorvehicle. If the transmission control device 6 detects that a motorvehicle is stopped at an incline or a decline for example, it can beconcluded that the vehicle mass has not changed, wherein thetransmission control device 6 does not recalculate the vehicle mass uponstart-up in the incline or in the decline. Furthermore, when thetransmission control device 6 detects that the motor vehicle was stoppedat a parking place for example, based on the topographic data 12 of thecurrent position of the motor vehicle, it can be provided that thevehicle mass is not recalculated at the next start-up because in thiscase also it can be concluded that the vehicle mass has not changed. If,however, the transmission control device 6 detects, on the basis oftopographic data 12 of the navigation system 11, that the motor vehiclehas reached its destination, then it can be concluded that the mass ofthe motor vehicle has changed at the destination so that the vehiclemass is recalculated at the next start-up.

Thus, as described above, the transmission control device 6 according tothe invention continuously calculates the driving conditions, vehiclemass and driving resistance and vehicle inclination on the basis oftopographic data 12 of the current position of the motor vehicles, thusdependent on the current position and the current incline or the currentdecline of the motor vehicle, in order to control and/or regulate theoperation of the transmission 2 more precisely on the basis of thiscurrently calculated driving condition data, namely to guarantee minimumfuel consumption with the greatest possible agility. In particular, theshifting strategy of the transmission control device 6 determines, onthe basis of this continuously calculated driving condition data, a gearchange from a current gear into a targeted gear while guaranteeing lowfuel consumption with great agility.

According to the second aspect of the invention, which can be used incombination with the details described above, the transmission controldevice 6 for controlling and/or regulating the operation of thetransmission 2 uses not only the topographic data 12 of the currentposition of the motor vehicle, but also topographic data 12 of a defineddistance ahead of the current position of motor vehicle. On the basis ofthe topographic data 12 of a defined distance ahead of the motorvehicle, the shifting strategy of the transmission control device 6determines a gear change from a current actual gear into a targetedgear, and again also depending on the driving condition data and thedata about the driver's wishes, wherein according to the second aspectof the invention the defined distance ahead of the motor vehicle, whosetopographic data is used by the transmission control device 6 in theshifting strategy, depends on the vehicle velocity. Thus, the defineddistance of the motor vehicle whose topographic data is used in thetransmission control device 6, namely in the shifting strategy of thesame, depends on the vehicle velocity such that the defined distanceahead of the motor vehicle is determined to be greater when the vehiclevelocity is greater.

According to an advantageous further development of this aspect of thepresent invention, the transmission control device 6 modifies counterincrement values of a shift monitor of the transmission control device6, depending on an inclination which is determined based on thetopographic data at the defined distance ahead of the motor vehicle. Ashift monitor is fundamentally known from DE 10 2005 005 379 A1, wherein terms of the invention, it is proposed that the counter incrementvalues of such a shift monitor be modified based on the topographic dataof a defined distance ahead of the motor vehicle.

In this context, the transmission control device 6 can modify thecounter increment values of the shift monitor so that when thedetermined inclination of the motor vehicle at the defined distanceahead of the motor vehicle is flatter, the shift monitor blocks tractivedownshifts. Furthermore, the transmission control device can modify thecounter value increments of the shift monitor so that when thedetermined inclination of the motor vehicle at the defined distanceahead of the motor vehicle is steeper, the shift monitor blocks tractiveupshifts.

Beyond this, depending on the topographic data at the defined distanceahead of the motor vehicle, the transmission control device 6 cancalculate a driving resistance-dependent rotational speed offset that isused by the shifting strategy in order to modify the targeted rotationalspeed of upshifts in traction mode. Therefore, it is possible toincrease the targeted rotational speed of upshifts in advance of anincline for example, so that such upshifts are no longer performed, andin contrast to a situation in which a decline is ahead of the motorvehicle. Here, targeted rotational speeds for upshifts in tractive modeare decreased, so that upshifts are performed earlier.

If the transmission control device 6 reads in the topographic dataregarding the defined distance ahead of the motor vehicle that the motorvehicle is operating in city traffic, the transmission control device 6can reduce or increase a driver's wish, which as a rule depends onactuation of an accelerator pedal, in the transmission control device 6.In the case of reducing the driver's wish, the transmission controldevice 6 simultaneously reduces a targeted rotational speed and a gearincrement for an upshift in tractive mode, wherein a maximum torque ofthe drive assembly can be limited by an engine engagement triggered bythe transmission control device. As a result fuel can be saved becausein city traffic as a consequence of speed limitations, a higher driver'swish is generally unnecessary. If, by contrast, a driver's wish isinternally increased by the transmission control device 6 in citytraffic, the targeted rotational speed for an upshift in tractive modeis simultaneously increased, and the shiftable gear increment isreduced. Upshifts in tractive mode are then triggered later, wherein itis possible for the driver to decelerate the motor vehicle using theaccelerator pedal.

Then, when the transmission control device 6 detects city traffic forthe motor vehicle based on the topographic data of a defined distanceahead of the motor vehicle, the transmission control device 6 can alsoinitiate a reduction of motor vehicle noise emissions. In this case, thetransmission control device 6 can reduce targeted rotational speed andgear shifts for shifting, in particular for upshifts in tractive mode,so that the vehicle is driven with lower engine rotational speed andaccordingly lower noise emission. Furthermore in this case, thetransmission control device 6 can deactivate an engine brake and/orswitch off an engine fan. For commercial vehicles in this case, the aircompressors which are necessary for providing pneumatic auxiliarybraking energy can be switched off for example.

In this context, the transmission control device 6 can switch on an aircompressor in due time before city traffic in order to sufficiently fillan air tank. Furthermore, in city traffic the transmission controldevice 6 can influence engine control for performing shifts for delayingthe torque build up and attainment, or start-up, of a synchronousrotational speed for engagement of a targeted gear.

If a crossing with a stop sign or a red traffic light, or a similarenvironmental situation of the motor vehicle is read based ontopographic data of a defined distance ahead of the motor vehicle, thetransmission control device 6 preferably internally increases a driver'swish, and a targeted rotational speed for an upshift is increased intractive mode so that a upshift in tractive mode is performed later. Ifthe transmission control device 6 reads a speed limitation from thetopographic data lying ahead of the motor vehicle, the transmissioncontrol device influences the upshifts in tractive mode using engineengagement, so that the maximum speed is not exceeded by the engineengagement. If the transmission control device 6 detects from thetopographic data applicable of a defined distance ahead of the motorvehicle that the motor vehicle is operated at high altitude, then for anupshift in tractive mode, a faster targeted rotational speed is set inorder to compensate for a power loss of the drive assembly using therelocation to an operating point with higher available torque.

As already described, depending on an incline which the transmissioncontrol device determines from the topographic data of a definedlocation lying ahead of the motor vehicle, the transmission controldevice modifies counter increment values of a shift monitor of thetransmission control device, and in particular for upshifts as well asfor downshifts in tractive mode.

In this context, the shift monitor using appropriately modified countervalue increments blocks tractive downshifts when the determined inclineat the defined distance ahead of the motor vehicle is flatter.

A shifting rotational speed of a shifting strategy for downshifts intractive mode is preferably influenced by a driving resistance-dependentrotational speed offset. As a result, the shifting rotational speed fordownshifts in tractive mode can be reduced before an incline and, ifapplicable, a downshift can no longer be performed. The drivingresistance and therefore also the driving resistance-dependentrotational speed offset is determined from the topographic data of adefined distance ahead of the motor vehicle. The transmission controldevice preferably also determines the gear increment to be implementedfor a tractive downshift depending on this determined drivingresistance-dependent rotational speed offset. Target rotational speedsfor coasting or tractive downshifts (shifts that are triggered byactuating the accelerator pedal) are calculated by the transmissioncontrol device 6 analogously to tractive upshifts, depending ondetermined driving resistance-dependent rotation speed offset.

According to an advantageous further development, the transmissioncontrol device 6, according to the invention, determines a tractiveforce that is necessary for traveling an incline lying at a defineddistance ahead of the motor vehicle. For this, from the engine dataprovided by the engine control device 5, the transmission control device6 calculates a minimum rotational speed that the drive assembly needsfor driving the incline, as well as an appropriate gear increment, andthen triggers the particular gear change.

Likewise, for influencing coasting upshifts, the transmission controldevice 6 according to the invention evaluates the incline from thetopographic data of a defined distance ahead of the motor vehicle.

When the transmission control device 6 detects that a plane follows asection of a decline, and with it a leveling off of the decline, thetransmission control device 6 performs an upshift in coasting mode inorder to reduce the engine braking effect of the drive assembly. In thiscontext, the transmission control device 6 preferably triggers theupshift only when the plane that is adjacent to the decline has aminimum length. If however, the transmission control device 6 detectsthat a plane with city traffic follows a decline, the coasting upshiftdescribed above is suppressed.

If, evaluating topographic data at the defined distance ahead of themotor vehicle, the transmission control device 6 detects that a steepdecline lies ahead of the motor vehicle or that the motor vehicle islocated at the start of a longer section of a decline, the transmissioncontrol device 6 according to the invention blocks coasting up shifts,and in the transmission 2 only shifts are permitted in order to protectthe drive assembly 1 from excessive rotational speed.

As already explained, the transmission control device 6 according to theinvention continuously evaluates the topographic data of a defineddistance ahead of the motor vehicle in order to determine progression ofthe incline, for example, at this defined distance ahead of the motorvehicle. If the transmission control device 6 according to the inventiondetects that the motor vehicle is currently located in a plane, butthere is a decline following the plane, then the transmission controldevice 6 according to the invention calculates which gear must beengaged in the transmission 2, so that the motor vehicle in the declinecan operate with constant drive speed through a braking effect of thedriving assembly using a so-called (engine) drag moment of the engine,while considering the available continuous braking power in the vehiclewhich can be provided for example by an intarder, for example.

If the transmission control device 6 determines that the continuousbreaking power is sufficient in order to travel the decline without aspeed increase, then the transmission control device blocks coastingdownshifts. In the other case, coasting downshifts are permissible. Ifnecessary, the transmission control device 6 can in this case activatean engine fan to provide additional braking power in order to avoiddownshifts in coasting mode.

The transmission control device 6 calculates targeted rotational speedsand gear increments for coasting downshifts in turn depending on adriving resistance or a driving resistance-dependent rotational speedoffset that the transmission control device 6 calculates from thetopographic data of a defined distance ahead of the motor vehicle.

If the transmission control device according to the invention detectsfrom the topographic data of a defined distance ahead of the motorvehicle that a curve would not be drivable with the current vehiclespeed, the transmission control device according to the inventiontriggers a downshift in coasting mode upon actuation of the operatingbrake, in order to attain a rotational speed level for the driveassembly with which a tractive mode of the motor vehicle is possibleupon completion of the curve. This way, the transmission control deviceaccording to the invention makes a shift possible in aconsumption-optimized rotational speed range of the drive assembly.

If the transmission control device 6 according to the invention detectsa traffic circle from the topographic data of a defined distance aheadof the motor vehicle, then the transmission control device 6 triggers acoasting down shift with release of a brake pedal or with deactivationof the continuous braking, specifically in such a way that in a targetgear of the gear change an acceleration reserve is provided for atractive mode.

As a result, spontaneous entry into the traffic circle is possible. Uponattaining the entry into the traffic circle or at a set distance aheadof same, the transmission control device 6 triggers in turn a coastingdownshift into a targeted gear in order to provide acceleration reservefor the tractive mode, and to enable a spontaneous entry into thetraffic circle.

When the transmission control device 6 according to the inventiondetects a crossing with a traffic light from the topographic data at thedefined distance ahead of the motor vehicle, coasting downshifts areblocked. If the transmission control device 6 according to the inventiondetects a highway on-ramp lane from the topographic data of a definedpoint lying ahead of the motor vehicle, coasting downshifts areautomatically performed despite a possibly present decline so that uponactuation of an accelerator pedal is sufficient acceleration reserve isavailable for acceleration of the motor vehicle.

The transmission control device 6 according to the invention cancalculate a fictitious driving resistance and an incline ahead of themotor vehicle from the topographic data at the defined distance ahead ofthe motor vehicle in order to decide whether a coasting mode or asailing mode is reasonable for the motor vehicle. The transmissioncontrol device 6 can then automatically trigger the coasting mode orsailing mode.

When the transmission control device 6 according to the inventiondetects from the topographic data of a defined distance ahead of themotor vehicle that the motor vehicle is not located on a street, theshifting strategy for starting up the motor vehicle can be influenced inorder to make it possible to start-up the motor vehicle safely in anoff-road situation.

A shifting strategy for a start-up can also be influenced by thetransmission control device 6 depending on the incline or the drivingresistance which lies at the defined distance ahead of the motorvehicle.

The invention is also used preferably for transmission control devicesfor commercial vehicles such as trucks for example.

REFERENCE CHARACTERS

-   1 drive assembly-   2 transmission-   3 output drive-   4 start-up clutch-   5 engine control device-   6 transmission control device-   7 data-   8 data-   9 data-   10 data-   11 navigation device-   12 data

1-13. (canceled)
 14. A transmission control device for at least one ofcontrolling and regulating operation of either an automatic or anautomated transmission of a motor vehicle, the transmission controldevice comprising: a shifting strategy which at least one of controlsand regulates the operation of the transmission based on at least one ofdriving condition data, vehicle mass, driving resistance, vehicleinclination, vehicle velocity, vehicle acceleration, engine rotationalspeed, engine torque, and also based on data about a driver's wishes,the transmission control device continuously calculating at least one ofthe driving condition data, the vehicle mass, the driving resistance andthe vehicle inclination based on topographic data of a current positionof the motor vehicle, the transmission control device, upon at least oneof switching on an ignition and at a standstill of the motor vehiclewith a switched on ignition, calibrating an inclination sensor based onthe topographic data of the current position of the motor vehicle, andthe transmission control device calculating, from the topographic data,a current vehicle inclination, and with the current vehicle inclinationcorrects a measured value of the inclination sensor.
 15. Thetransmission control device according to claim 14, wherein thetransmission control device, during travel of the motor vehicle,calculates a current driving resistance from the topographic data,rolling resistance, aerodynamic resistance and from the vehicle mass.16. The transmission control device according to claim 15, wherein forthis purpose the transmission control device calculates the currentrolling resistance from the topographic data, current tractive force,current aerodynamic resistance and from current vehicle acceleration.17. The transmission control device according to claim 16, wherein thetransmission control device determines a current tractive force from acurrent engine torque and a current vehicle acceleration either bymeasurement or calculation from the current vehicle velocity.
 18. Thetransmission control device according to claim 14, wherein thetransmission control device during travel of the motor vehiclecalculates a current vehicle mass from at least one of the topographicdata, aerodynamic resistance, rolling resistance, current vehicleacceleration and current tractive force.
 19. The transmission controldevice according to claim 14, wherein the transmission control, deviceduring a start-up of the motor vehicle from a standstill, calculates acurrent vehicle mass.